Exam 4 Physio: Renal 2

Front 1

EXAM 4 PHYSIO: RENAL 2

Back 1

EXAM 4 PHYSIO: RENAL 2

Front 2

Proximal tubule

Back 2

Most reabsorption takes place here.

Front 3

Transcellular uptake is mostly driven by:

Back 3

Secondary active transport coupled to Na gradient.

Front 4

Paracellular uptake is driven by:

Back 4

Concentration gradient

Voltage in some cases coupled to water movement

Front 5

Curves illustrated by glomerular filtration, reabsorption, and excretion against plasma glucose concentration?

Back 5

1. filtration: linear relationship
2. reabsorption: saturation process-- plateaus out.
3. excretion: mirror image of reabsorption curve.


Draw out curve of excretion:






Here.

Front 6

What is Tm (transport maximum)?

Back 6

Maximum rate at which substrate can be reabsorbed.

Front 7

Reasons for why Tm occurs?

Back 7

1. limited # of transporters
2. kinetic saturation of transporters

Front 8

Diabetes Mellitus

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1. loss of reg of plasma glucose thru insulin.
2. inc. glucose and ketone bodies.
3. filtered load of glucose exceeds Tm of proximal tubule to reabsorb all glucose.
4. non-absorbed glucose passed on to distal tubule is osmotically active--> impairs ability of CD to reab. water.
5. abundant amout of glucose in tubule causes water to follow, therefore, urine formation is excessive--> diuresis and glucosuria.

Front 9

What is the purpose of distal portions of renal tubule?

Back 9

Fine tuning the reabsorption of some electrolytes.

Purpose is to match excretion rates to rates of intake/generation.

NOTE: tubule tries to balance output and input!

Front 10

Maintenance of steady state requires?

Back 10

Energy expenditure!

Front 11

Types of pumps involved in certain tubular segments for PROXIMAL TUBULE:

Back 11

1. Na-H exchanger
2. Na-X cotransporter

Front 12

Types of pumps involved in certain tubular segments for ASCENDING LIMB:

Back 12

1. Na-K-Cl cotransport

Front 13

Types of pumps involved in certain tubular segments for DISTAL TUBULE:

Back 13

Na/Cl

Front 14

Types of pumps involved in certain tubular segments for CD:

Back 14

Na passes right through.

Front 15

Basolateral membrane

Back 15

On side closes to blood

NOTE: apical: adjacent to lumen.

Front 16

What type of transport occurs at the basolateral membrane?

Back 16

Secondary active or passive apical entry.

Front 17

Recycled Potassium (K) occurs where?

Back 17

Basolateral membrane.

Front 18

Cl and H2O are transported how?

Back 18

Downhill

Front 19

Where will these go in the body and what are their osmotic consequences?
Ethanol, KCl, and NaCl

Back 19

Ethanol: everywhere, intra/extracellular

KCl: kept intracellular by Na-K ATPase pump. Will draw water into intracellular compartment.

NaCl: kept extracellular by Na-K ATPase pump. Will keep water in extracellular compartment.

Front 20

Consequence of a drop in MAP?

Back 20

Constriction of renal afferents and reduced GFR.

Front 21

Renin-angiotensin-aldosterone signaling:

Back 21

Angiotensinogen (from liver)--> Angio I (via renin from kidney)--> Angio II (via converting enzyme)--> aldosterone to stimulate salt and H2O retiontion (adrenal cortex) or vasoconstriction--> inc BP

Front 22

Atrial natriuretic peptide

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Promotes vasodilation--> inc GFR.

Inhibits Na reab in distal tubule leading to natriuresis (Na in urine)--> inc urine vol and dec BP.

Front 23

How does ADH work?

Back 23

By inducing insertion of water channels into apical membrane of CD--> inc water reab.

Also vasocontricts in peripheral circulation.

Front 24

Higher MAP means what?

Back 24

Higher driving force for blood flow through renal circulation and for filtration in the glomerulus.

Front 25

Low BP due to cardiac insufficiency can lead to?

Back 25

Fluid retention via low GFR and dec excretion by kidney.